Speed retarding and reversing device.



G DEVICE. 1906.

APPLIGA'IIO1 I FILED APR. 19

Patented May 10, 1910- Witnesses ANDREW n GRAHAM cow PHOYOMHOGRAPNERS mswmuwu u c KARL JOI-IAN ALBERT ISAKSON, 0F STOCKHOLM, SWEDEN.

SPEED RETARDING AND REVERSING DEVICE.

Specification of Letters Patent.

Patented May 10, 1910.

Application filed April 19, 1906. Serial No. 312,630.

To all whom it may concern:

Be it known that I, KARL J OHAN ALBERT ISAKSON, of Strandvagen 11, Stockholm, Sweden, have invented certain new and useful Improvements in Speed Retarding and Reversing Devices, of which the following is a specification.

The principal reason, why motors have not yet succeeded in taking the place of steam engines for propelling larger cargoand passenger-vessels, is due to the fact, that both explosive and internal combustion en gines (such as the Diesel motors) are actuated by intermittent motive power, necessitating the employment of heavy fly-wheels, which cannot at once be reversed without risk of breakage to one or other of the moving parts, due to the considerable amount of energy, stored in the revolving and reciprocating masses.

To effect the reversing by the simple method used in some small boat motors, of igniting the explosive gases sufficiently early in the return stroke of the piston, is of course out of the question in large motors, and equally impracticable in large motors is the employment of mechanical reversing gears of various kinds (such as cog-wheelor friction gearings, belt or rope transmission etc.), although they may be used with great advantage in smaller vessels with light machinery. The same applies to a certain extent also to the method of reversing the motion of the vessel by reversing the pitch of the propeller blades. The endeavors of the numerous inventors, working on the solution of this very important problem, have generally been bent on the discovery of some com bination, by means of which slow speed and reversal of the propeller might be effected without reversing the motor itself, or, in some cases, even without altering the speed of the motors. A very successful and ingenious solution, from a purely technical or rather from a designers point of view, of this problem consists in fitting the motor with a dynamo on the elongated crank shaft. By means of a controller on the bridge or maneuvering platform of the ship and an electromotor at the front end of the propeller shaft, it is possible to obtain, at any moment desired, almost every degree of slow speed and back motion of the propeller, without in the least altering the direction and the speed of the motor itself. This ingenious appliance has been used in practice on board some cargo-vessels of about 700 tons displacement, trading on the Volga river, although the electric transmission plant means a considerable increase both in the weight of the machinery and in the initial cost.

The object of the invention, herein described, is an arrangement for the same purpose, viz: moderating or reversing the motion of motor-ships without interfering with the direction of movement of the motor itself. It does, however, not materially increase the weight or the initial cost of the machinery, as compared with these two items in a common, non-reversible explosive or internal combustion engine for use 011 land.

I will first proceed to briefly review the general considerations, that conduced to this invention. It is evident, that in both war-, passengerand ordinary cargovessels, apart from such smaller craft as crossriver ferry boats, the time during which the propeller or the paddle wheels, as the case may be, are running slow or astern, is only a very small fraction of the whole running time of the engines. Consequently, with regard to the fuel economy, it is not a very important matter, that the appliance for moderating the speed or reversing the motion of the vessel should be, as regards its thermal action and thus economically, of a very elaborate or eflicient character. The main point is, on the contrary, that this gear should be, in its working, absolutely reliable, so that collisions or other mishaps could be evaded with at least the same security as when using a reversible steam engine. This line of argument is the parent of this invention, which, in principle, consists in the combina tion of a motor with a powerful jet-apparatus or ejector, directed ahead, and strong enough to efliciently stop and reverse the vessels headway or moderate its speed, as may be required. Steamor water-jets as means for marine propulsion, as is well known, have been tried very long ago on the British gunboat lWaterwitch and also on a small sloop of the Swedish navy, but, owing to the very high consumption of fuel, these experiments have not had many followers. Neither the motor itself, nor the waterjet-apparatus generally thus forms the object of this invention, but the new combination of both these previously well known arrangements, by which the problem of slowing the speed and effecting motion astern in motor-vessels is solved in a reliable manner.

In the drawings, Figure 1 represents a vertical longitudinal section. Fig. 2 represents a vertical cross section of a ship, fitted with the waterjet apparatus, herein described, together with the ordinary motordriven propeller. Fig. 3 is a vertical longitudinal section of the water et apparatus.

The waterjet-apparatus may consist, for example, of an accumulator cylinder or cylinders a, into which air or other gas or mixture of gases is compresssed and stored, until required. The compressed airor gas-cushion, which may be kept over a small quantity of water in the accumulator, supplies the necessary motive power for reversing the motion of the vessel. In such motors, for instance as the ordinary Diesel-motors, in which a separate air compressor is already a component part of the machinery, the accumulator may be supplied with air at a pressure of say 40 atmospheres from this compressor. Also chemical means may be used for producing the necessary quantity of compressed air or gas. The compressed air or gas is led through a pipe E to the ejector 0 and the required quantity of water and air or gas on each occasion is regulated by means of a stop valve (Z on this pipe. The motor 6 can also be so arranged, that, when the vessel is going astern, the whole power of the motor is employed in compressing air for the accumulator, in order to prevent the air pressure from falling too rapidly. \Vhen two or more accumulators are used, they are connected to each other by means of air pipes 09, in order to maintain the same pressure in both or all of them and thus maintain equal efliciency in both or all the ejectors.

In order to evade damage to the ejectors and to prevent them from being stopped with grass, mud or ice, they are preferably arranged as one or more elbow-bent casings, fitted in the vessels bottom, the inlet being in addition fitted with an ordinary protective grating. By thus storing a large amount of energy in one or more accumulators and letting it suddenly loose in the lapse of a short time (from say 20 seconds in a smaller craft to one or two minutes in large vessels) the horsepower, at disposal for stopping and reversing the vessels headway, is not limited to the maximum power of the propelling machinery, as with ordinary reversible steam engines or reversible motors, but may be increased to twice, thrice or several times the ordinary maximum horse power of the propelling machinery. This feature of the invent-ion is of prime importance, as it embodies a vast increase of safety at sea by facilitating a much more sudden stoppage of a vessels headway than has been possible with any arrangement hitherto practiced. The propeller shaft f should however preferably not be bolted to the thrust shaft by afixed coupling, as in steam engines, but should be connected to it by means of a suitable clutch coupling 9, so that (in cases of emergency and when a very sudden stoppage of the vessel is necessary), when the ejector is put in use, the propeller shaft is at once disconnected. Thus, in cases of emergency, as in view of an imminent collision, the jet will not have to overcome anything more than the vessels own energy. By this arrangement, the retarding action will thus be more eflicient and sudden than in any vessel of corresponding size and engine power, at present afloat.

In Fig. 8 is shown one of the forms, in which the waterjet-apparatus may be preferably constructed. The driving medium is distributed as intimately as practicable into the water volume acted upon, in order to obtain a powerful reaction. The apparatus consists of a bent pipe A, opening with both ends in the ships bottom or side D be low the waterline. This pipe is penetrated by a number of channels B, directed ahead, through which channels the driving medium is supplied to the ejector. G is a channel, arranged around the pipe, in order to more uniformly distribute the medium. The suction end of the ejector is widened, as shown, in order to facilitate the free access and ready acceleration of the water, entering from the sea into the ejector. By means of a regulatingand stop valve cl, inserted in the feed-pipe E and manipulated in the usual manner by a screwspindle and handwheel, or other similar gear, the driving medium is admitted from the accumulator in the quantity required. \Vith fully open valve, the vessel can be stopped and driven astern, even if the propeller shaft is not disconnected, 6. running continuously ahead, if only the waterjet-apparatus is of sufiicient size, so that the horse power, developed by the waterjet is greater than that, developed by the propeller. If the propeller shaft is disconnected, the stopping and the astern-motion is still more effectively carried out, and the vessels astern motion is more rapid. The speed astern is, in addition, very eifectively and accurately governed through a partial shutting or opening of the valve (Z. Also, when running ahead at full speed, the vessels speed can be momentarily decreased, as required (in order to evade the course of another passing vessel, when in a fog or in narrow or crowded water courses, and the like), through operating both or one of the stop valves without disconnecting the propeller shaft or stopping the engines, which are thus still running full speed ahead. This invention thus also afi'ords a means for increasing safety against the frequent casualties, which occur both in motor boats and steam propelled vessels (where the machinery is arranged for running both ways) through the engines occasionally refusing to be reversed.

It is evident, that, by fitting two waterjets, one 011 each side and somewhat apart from the keel, the keel is left undisturbed, and the same advantages are obtained re garding steering operations, turning on the spot, etc., which accompany both the use of twin propellers, each driven by its own engines, and the arrangement in the Waterwitch above referred to.

The principal feature of this invention is thus the combination of propulsion motors running in one direction only and propelling the vessel by means of screws or paddle wheels, etc., with a jet-apparatus for effecting stoppage and asternmotion and for momentarily moderating the speed (ahead or astern) of vessels propelled by such motors.

Having thus what I claim is:

1. In motor vessels, the combination with a motor running in one direction only for driving the vessel ahead by means of a propeller fitted on a shaft, driven by the motor in the usual manner, of a jet-apparatus or ejector in the form of a tube bent angularly and comprising a long and a short branch open at both ends for moderating the Vessels speed and for reversing the direction of the vessels motion from ahead to astern, when required, substantially as described.

2. In motor vessels, the combination with a motor, actuating a propeller in the usual way, of a jet-apparatus in the form of a tube bent angularly and comprising a long described my invention and a short branch open at both ends, fed from an accumulator, in which compressed air or other gas or mixture of gases is stored or produced, for moderating the vessels speed and for reversing the direction of the vessels motion from ahead to astern, when required, substantially as described.

3. A jet-apparatus for stopping and reversing a vessels headway, composed of a pipe or tube angularly bent into a short and a longer branch open at both ends and secured under the water line upon the hull of a ship, the open ends communicating with the sea, in line or parallel with the longitudinal axis of the ship, the longer branch ahead and the shorter branch astern in combination with a tube E for a pressure fluid surrounding the bent pipe near the apex of the bent angle and having a number of inclined perforations directed toward the opening of the longer or forward branch.

4. A jet-apparatus for stopping and reversing a vessels headway composed of a pipe or tube, angularly bent, open at both ends and secured under the water line upon the hull of a ship, the open ends communicating with the sea in combination with a tube E for a pressure fluid, surrounding the bent pipe near the apex of the bent angle and having a number of inclined perforations, directed toward the opening of the forward branch.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

KARL JOHAN ALBERT ISAKSON.

lVitnesses HJ. FETURsrnoM, BIRGER NORDFELDT. 

